LVM *was* Re: [mythtv-users] Highest number of simultaneous streams recorded?

[Steve Adeff]

On Friday 14 October 2005 14:25, Alex Brekken wrote:
> Steve, is there any way to add an LVM on an up-and-running system, or must
> it be done during the OS install when partitioning the disk? (sorry, I
> don't mean to hijack this thread but I figured this would be a quick
> answer) Thanks!
>
> On 10/14/05, Steve Adeff <adeffs at gmail.com> wrote:
> > On Friday 14 October 2005 10:16, Brandon Beattie wrote:
> > > The current limitations on number of streams has to do with what
> > > hardware you choose to use. This includes tuner cards, hard drives,
> > > network cards, and CPU. I think it would still be rather easy to get
> > > 10+ streams recording and 4-5 being played back (1 local, 3-4 remote)
> > > before you see any problems. To do this you would need either hardware
> > > assisted analog encoders, or an HD tuner because they won't use more
> >
> > than
> >
> > > 3% or so CPU. To reach a 10Rec 5Play number, you would want a good
> > > processor and memory, something 3.4Ghz or over would be fine -- If
> > > you're not going to watch video locally though, I bet you could do all
> > > this with 2Ghz or less. Disk usage is the next issue. Using raid
> > > 0, 5 or 10 would help in this areas you may be able to do 15 streams
> > > total with 2-3 striped drives I would bet. Networking will be the final
> > > issue. HD streams run up to just under 20Mb/s. As much as we wish to
> > > get 1Gb/s speeds all the time, expecting much over 400Mb/s constant is
> > > not always possible. Myth struggles to play video smoothly unless it
> > > feels like it has room to breath and almost no packet loss.
> >
> > another option if you find yourself recording this much is to use LVM
> > (logical
> > volume manager). It would allow you to connect, say four 300gig drives
> > and use them all as one AND stripe data across them (like RAID 0). Or you
> > could
> > use 3 striped and the 4th as a parity drive in case one dies.
> > This would most definitely give you the drive speed required to not only
> > record 4+ streams at once, but play back equally as many.
> >
> >
> > Steve

from my understanding, yes it is, and properly set up you can also add and 
remove drives from an LVM at any point as well. I recently discovered LVM so 
I've yet to implement it, but I did a good amount of research and it seems to 
be quite easy now and I did not see anything that made me think I'd have to 
reinstall. Of course, I wouldn't use a LVM for your root partition, at least 
until you know what your doing... I'm just going to be using it for my 
storage drives.


Steve